Change test_htmlparser to reflect the HTMLParser -> html.parser
rename in r63439.

Also fix one occurrence of unichr() in html.parser.
diff --git a/Lib/html/parser.py b/Lib/html/parser.py
index 352a788..828eece 100644
--- a/Lib/html/parser.py
+++ b/Lib/html/parser.py
@@ -378,7 +378,7 @@
                 if HTMLParser.entitydefs is None:
                     entitydefs = HTMLParser.entitydefs = {'apos':"'"}
                     for k, v in html.entities.name2codepoint.items():
-                        entitydefs[k] = unichr(v)
+                        entitydefs[k] = chr(v)
                 try:
                     return self.entitydefs[s]
                 except KeyError: